Severe hot weather forecast for Victoria over coming days is being compared to the conditions ahead of the devastating Black Saturday bushfires of 2009.
Temperatures are expected to reach the high 30s and low 40s across the state on Thursday and remain elevated overnight before hitting a top of 43C in Melbourne on Friday.
A cool change is expected late on Friday, bringing wind gusts of up to 80km/h, thunderstorms and increased fire risk.
Country Fire Authority chief officer Steve Warrington said Friday would mark the "first real day" of bushfire risk for the whole of the state this summer.
"We know - based on our history - that unfortunately, we have lost lives, we have lost property, we have lost stock and there has been significant damage," he told reporters on Wednesday, drawing a comparison with 2009.
"It is time for all Victorians to be aware for the next four, six and up to eight weeks."
Bureau of Meteorology senior meteorologist Richard Russell described the cool change as a "double-edged sword".
"Fire danger will increase - we've got severe to extreme fire dangers pretty much across the state during Friday," he said.
"Thankfully the humidity does help keep that fire danger from getting incredibly high but it also means that it's very uncomfortable."
Mr Russell described Thursday's forecast overnight high of 29C - just shy of the state's overnight record of 30.6C - as "oppressive".
While fire crews are ready to battle expected blazes, extra paramedics and ambulances will be on call to assist those struggling in the heat.
"Heat can kill," Emergency Management Commissioner Andrew Crisp said.
"Some people refer back to the 2009 fires but we know that 370 people lost their lives because of the heat at that time. But we've learnt and we've come a long way since 2009."
